Post-LASIK corneal epithelial irregularities October consultation #1

A 55-year-old man with a history of bilateral laser-assisted in situ keratomileusis (LASIK) and subsequent enhancement over 15 years ago presented to our facility to investigate refractive surgery options. The patient reported progressive blurring and fluctuation of vision and desired independence from contact lenses and spectacles. Uncorrected distance visual acuity (UDVA) was 20/30 -2.0 in the right eye and 20/400 in the left eye, corrected to 20/60 in the left eye. Manifest refraction was +0.75 -1.75 × 180 diopters (D) in the right eye and -3.50 -3.50 × 64 D in the left eye. Keratometry readings were 43.9/41.1 @ 25 in the right eye and 49.3/46.8 @ 2 in the left eye. On slitlamp examination, the patient showed diffuse subepithelial fibrosis and confluent circumferential elevation, respecting the LASIK flap margin and extending centrally into the visual axis (Figure 1JOURNAL/jcrs/04.03/02158034-202110000-00025/figure1/v/2021-09-20T141830Z/r/image-tiff). Fluorescein pooling was also observed. Anterior segment ocular coherence tomography (OCT) demonstrated subepithelial hyperreflective density in the left eye (Figure 2JOURNAL/jcrs/04.03/02158034-202110000-00025/figure2/v/2021-09-20T141830Z/r/image-tiff). Pentacam showed irregularity and inferior steepening up to 52.0 D (Figure 3JOURNAL/jcrs/04.03/02158034-202110000-00025/figure3/v/2021-09-20T141830Z/r/image-tiff). A review of the patient's records from 4 years ago revealed UDVA of 20/30 -2 in the right eye and 20/20 in the left eye with manifest refraction of +1.00 -1.50 × 30 D in the right eye and -0.25 D in the left eye. Keratometry then showed 39.52/40.91 @ 98 in the right eye and 39.85/40.42 @ 75 in the left eye. Patient's slitlamp examination revealed minimal subepithelial irregularity without endothelial changes in both eyes. At current presentation, the patient was not deemed a candidate for further refractive surgery given a low residual stromal bed after original LASIK with enhancement. The patient was seeking help and advice for his declining vision. What is the most likely diagnosis, and what other conditions are on your differential? What would be your next step? Would you request additional diagnostic workup? What medical and surgical interventions would you recommend?